Expansion shield



April 29, 1930. L. R. ZIFFERER EXPANSION SHIELD Filed Sept 9. 1927 ot izar Patented Apr. 29, 193% EXPANSION SHIELD Application filed September 9, 1927. Serial No. 218,473.

This invention relates to the shield component of an expansion bolt, and more par ticularly to a shield which is formed from sheet metal by die operations.

The object of the present invention is primarily to provide a shield of this character which is inexpensive, sturdy, easily assembled and installed, and dependable in its operation. It is also an object to so bend the metal of the shield as to provide certain ribs for contact with the surrounding walls of the aperture in which the expansion bolt is anchored, and other internal ribs which receive pressure from a tapering expanding member which is movable lengthwise of the shield. In the form shown the present invention is applied to an expansion of'the indirect type, i. e., one in which the spreading of the shield sections is accomplished by means other than the bolt which engages the work.

A suggestive embodiment of this invention is set forth in the accompanying drawings wherein t Figure 1 is a new in elevation of the expansion shield in its collapsed condition;

Fig. 2 is a similar view showing the relation of the shield parts after expansion has taken place;

Fig. 3 is an enlarged longitudinal section through the shield as it appears during expansion;

Figs. 4 and 5 are transverse sections through the shield taken on lines 4-4 and 5-5, respectively, of Fig. 3;

Fig. 6 is an elevation looking toward the inner end of the shield; and

Figs. 7 and 8 are views in planof the blanks from which the two shield sections are formed.

The shield of my present invention comprises two complementary sections A and B,

g each in the general form of a half cylinder.

Near the outer end of each section is a neck 10, a pair of lugs 11 being extended from the one to embrace the other. In this manner, the two shield sections are held in assembled relation. A head 12 is provided at the outer end of each section, and at the opposite end of the neck 10 is a shoulder 14 of substan-- tially the same height. The body of the shield comprises certain external ribs 15 extending lengthwise from the shoulder to the rear end thereof. These external ribs lie in termediately of certain internal or cam ribs 16 which, as shown best in Fig. 3, extend from the rear end of the shield inwardly and then outwardly again as at 17.

A. reference to Figs. 4, 5 and 6 discloses a peculiar cross sectional contour. In the form shown, six internal ribs are providechthree on each shield section. By comparing Figs. 4 and 5, it will be noted that the central rib 16 is tapered to a considerable extent whereas the adjacent ribs 18 are slanted inwardly scarcely if at all. These side ribs, however, proceed at a slight angle relative to the shield axis so as to approach in a small degree the central rib at the inner shield end. Between the two sections so formed,I place an expander, preferably in the form of a hexagonal .nut 19, with tapering sides conforming generally to those of the central or cam ribs '16. This nut is internally threaded to co-operate with a bolt 20 having a head 21 which lies beyond the outer shield end to engage with the work. If desired, one of the shield sections may be provided with a laterally extended lip 22 which lies beyond its inner end for the purpose of holding the expander against loss, this lip being yieldable in response to an end'thrust of the bolt when occasion may require. v It will be noted in the construction set forth that the nut exerts opposite pressures upon the central ribs 16 of thetwo shield sections. Against the adjacent ribs no radial force of consequence is directed, their function being primarily to guide the nut nonrotatably in its travel during the expanding operation. I During this movement the side ribs engage with the expander at shifting points due to the angular disposition of these ribs relative to the bolt axis. I may find it desirable also to serrate transversely as at 23 the outer ribs 15 so as to enhance their frictional gripping powers withthe wall surrounding the aperture wherein the device is anchored.

' polygonal expander movable longitudinally how simple a form of blank is needed for the production of the shield sections already described. In the forming operations, the metal is so treated as to retain its full strength at every point. Because of the simplicity and peculiarity of the rib formations,

it is possible-to form each shield section without drawing out or attenuating the metal at the points where the greatest strains are en countered. In fact, the ribs which .receive expansive thrusts from the expander andthose which transmit such thrusts to the surrounding walls of the aperture in which the device is anchored are of slightly increased thickness. This is an important advantage and one which makes for a sturdier shield.

I claim:

1. An expansion shield comprising sub-- stantially semi-cylindrical sheet metal sections adapted when assembled to form an expansible substantially cylindrical body having cross-sectional convolutions in the form of ribs extending lengthwise of the shield,v certain of the ribs being outwardly protruded at a-unifor n height, other-of. the ribs being inwardly protruded and inclined inwardly from the inner end of the shield, and still other ribs having an inner protrusion at an angular disposition relative to the shield. axis and the remaining ribs, and a of the shield having inclined surfaces engaging the inwardly protruded inclined inner ribs, and adapted to exert a radial force against said ribs and expand the shield,f said expander also having other surfaces pres? sented to the angularly disposed ribs and V l adapted to be prevented by said ribs from rotation relative to said shield. i V

' 2. An expansion shield comprised of two complemental substantially semi-cylindrical sheet. metal sections formed to provide an expansible cylindrical body having internal longitudinal ribs substantially parallel to the axis of the body 'and inclined inwardly from the inner end of the shield, and a non: circular expander movable longitudinally of the shield in engagement with said ribs and adapted to direct a radial force thereupon, and other longitudinally disposedinternal ribs cooperating with the expander for guiding and preventing relative rotation of the same, said last named ribs extending longitudinally at an angle relative to said first mentioned'ribs. 3. An expansion shield comprising a substantially cylindrical sleeve having expansible sections, said sleeve being formedwith in ternal cam ribs, an expander for said sleeve adapted to cooperate with said cam ribs, said sleeve being further provided with an in- 1 ternal rib on each side of the cam rib'for guiding and preventing rotation of the expander. V V LO THAR R. ZIFFERER; 

